add Visitor in example

examples/example.sql

@@ -17,6 +17,21 @@
 SET NAMES utf8mb4;
 SET FOREIGN_KEY_CHECKS = 0;
 
+-- ----------------------------
+-- Table structure for category
+-- ----------------------------
+DROP TABLE IF EXISTS `visitor`;
+CREATE TABLE `visitor`
+(
+    `id`         int          NOT NULL AUTO_INCREMENT,
+    `ip`         varchar(200) NOT NULL UNIQUE,
+    `updated_at` datetime(6)  NOT NULL DEFAULT CURRENT_TIMESTAMP(6) ON UPDATE CURRENT_TIMESTAMP(6),
+    `created_at` datetime(6)  NOT NULL DEFAULT CURRENT_TIMESTAMP(6),
+    PRIMARY KEY (`id`)
+) ENGINE = InnoDB
+  DEFAULT CHARSET = utf8mb4
+  COLLATE = utf8mb4_general_ci;
+
 -- ----------------------------
 -- Table structure for category
 -- ----------------------------